Breech structure of guns



G; M. MCCANN l Fir-E- Kf, w

wf//W May 6, 1936.

Patented May 6, 1930 GEORGE IVI. MCCANN, F NEW CASTLE, DELAWARE BREECI-I STRUCTURE 0F GUNS Application filed January 24, 1929. Serial No. 334,804.

(GRANTED UNDER THE ACT OF MARCH 3, 1883, AS AMENDED APRIL 30, 1928; 370 0. G. '757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to breech structure of guns.

In the most successful type of gun with removable liner, an initial clearance or play space exists between the liner and the surrounding tube. The liner is thin and under the stress of firing; it dilates into Contact with the tube and then both elements expand together.

The tube confines the liner within its elastic limit and by preventing deformation insures the reestablishment ofthe initial clearance. lnasmuch as the liner is intended for quick replacement in field the breech structure of the gun must be formed to permit rey 2c moval and insertion of the liner without dismantling the gun.

The purpose of this invention is to provide means for retaining the liner in place which will conform to the action of the liner and tube during firing, which will be capable of ready attachment and removal and which will not interfere with the operation of the breech block and cartridge extracting mechanism. y

With the foregoing and other objects in view, the invention resides in the novel arrangement and combination of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the invention.

A practical embodiment of the invention is illustrated in the accompanying drawings,

wherein:

Fig. l is a longitudinal sectional view through the breech end of the improved gun;

Fig. 2 is a detail view of the retaining ring;

Fig. 3 is an enlarged sectional view through a portion of the breech end of the gun, the play space being exaggerated.

Referring to the drawingsby numerals of reference Ci' The gun embodying the principles of the invention comprises a tube 5 within which is a liner 6 made of steel having a high elastic limit, this quality being incident to the particular composition of the metal or produced through methods of working or both. In order that the original dimensions of the tube may be preserved irrespective of the lextentY of its use the inner layer of the tube shouldV also be overs-trained by working to give it a permanent set of deformation to insure uniformity and the absence of defects.

In the preferred form the interior of the tube is slightly tapered from breech to muz- Zle and the exterior of the liner is correspondingly tapered to facilitate its insertion and es removal in the tube. Between the walls of the tube and liner a play space or clearance 7 is maintained and this clearance is so determined, allowing for tolerances in manufacture, that the liner will not exceed its elasfe tic limit when it dilates to and with the tube under the stress of firing. Consequently, when the internal pressure is relieved, the liner and tube are restored to their original dimensions and the play space is reestablished.

The liner upon being placed in position in the tube is held against retraction by the internal liange 8 of a retaining ring 9 secured as by threading 10 to the tube. The eX- tremity of the tube is reduced as at 11 to provide an annular recess for receiving the iange of the retaining ring which is thereby enabled to be substantially flush with the end faces of the liner and tube and will not interfere with the breech block. In order that the retaining ring may function as a part of and in exactly the same manner as the tube in confining the liner within its elastic limit, it preferably possesses the same physical qualities as the tube imparted by cold working, if necessary, and a play space 12 is pro` vided between the ring and liner, this space conforming or substantially conforming to that existing between the tube and liner. In this way the ring is free to be removed evenk after extended firing.

The breech ring 13 secured to the tube is formed with a breech block recess 14 arranged and dimensioned to permit removal of the 100 breech block (not shown), the application of a tool for engaging the radial grooves l5 in the ring, and removal or the ring and liner.

I claim:

l. A gun comprising an outer tube, a liner, the outer diameter of the liner being less than the inner diameter of the outer tube to establish a play space restorable after firing, a. retaining ring securable to thetube and formed With a flange engageable With the liner, the rear face o the ring being substantiall7 flush with the rear faces of the tube and liner7 and the inner diameter ofthe ring being greater than the outer diameter of the corresponding part or" the liner to establish a play space.

E2. gun comprising an outer tube, a liner, a retaining ring securable to the tube and engageable With the liner, the rear face of the ring being substantially flush with the rear face oi: the liner, a breech ring on the tube ha fing a breech block recess dimensioned for removal of the ring and liner.

3. gun comprising an outer tube, a liner, a retaining ring securable to the tube and engageable with theliner and abreech ring on the tube having a breech block recess dimensionedfor removal of the ring and liner.

4l. A gun comprising an outer tubehaving a bore 'taperedfrom breech to muzzle, a similarly tapered liner insertedin the bore of the tube, the outer diameter of the liner being less than the inner diameter of the tube, whereby the liner is loose in the tube, and a retaining member securable in the breech end of the tube and extending into the path ot Withdrawal of the liner.

GEORGE M. MCCANN. 

